Abstract: The present invention provides a process for purifying the cinnamoyl-C-glycoside, 8-C-.beta.-D-?2-O-(E)-cinnamoyl!glycopyranosyl-2- ?(R)-2-hydroxy!propyl-7-methoxy-5-methyl-chromone, referred to herein as the "540 compound." In one embodiment of the present invention the 540 compound is purified by extraction from a decolorizing agent with an organic solvent. The extracted product can be further purified by high pressure liquid chromatography. In a second embodiment crude 540 compound, which has not been treated with a decolorizing agent, is purified by passage over neutral alumina or sephadex.